This invention relates to an improved process for the production of arylakyl phosphines, phosphine oxides and phosphine sulfides. The process comprises the reaction of an alkyl phosphine, phosphine oxide or phosphine sulfide with an arylhalide in the presence of a zero valence palladium catalyst. This process has the advantages of fast reaction rates at relatively low temperature, avoidance of phosphine halides and Grignard reagents and a relatively simplified work-up of reactants.
The preparation of arylalkyl phosphines, phosphine oxides and phosphine sulfides is known in the art. However, previous processes for the preparation of these compounds involve the use of reagents which are either cumbersome to work with or entail the need for detailed work-ups and extraordinary production conditions and precautions.
U.S. Pat. No. 3,775,482, for example, disclose the use of alkali metal whereby tetrahydrocarbyl diphosphines are reacted therewith in a solvent such as tetrahydrofuran and the resultant phosphide is isolated. A fused ring polynuclear aromatic hydrocarbon or diphenyl is used as a catalyst.
U.S. Pat. No. 4,618,720 discloses a two-step process whereby a diphenylphosphinous halide is reacted with a molten alkali metal in the presence of an inert solvent and the resultant diphenylphosphinous metal is then reacted with a second halide wherein an excess of molten alkali metal is employed and the second halide is added in situ.
U.S. Pat. No. 4,668,823 teaches the production of alkylarylphosphines by the sequential addition of different Grignard reagents to aryldichlorophosphines. The first Grignard reagent having an alkyl group is reacted with an aryldichlorophosphine and the resultant arylalkylchlorophosphine is reacted with the second Grignard reagent having a different alkyl or aryl groups.
U.S. Pat. No. 5,288,912, and its divisional counterpart U.S. Pat. No. 5,354,894, teach the preparation of alkyldiarylphosphine compounds by the reaction of alkali metal diarylphosphides with alkylhalide alkylating agents via lithium cleavage.
Cabri et al, J. Org. Chem. Vol. 57, pgs. 355-3563, 1992, teach the arylation of unsymmetrical olefins using bidentate phosphine containing palladium catalysts.
Ono et al, Tetrahedron Letters, Vol. 35, No. 24, pages 4133-4136, 1994 report on the arylation of N-alkyI-O-allyl carbamates using a palladium catalyst.
In Synthesis, March 1991, pages 232 and 233, Loffler et al report on the coupling of (1,3 -butadiynyl) amines with aryl and vinyl iodides using a palladium catalyst and in March 1986, pages 240-242, Xu et al teach the use of palladium catalysts to synthesize alkyl alkenylmethyl and alkenylphenylphosphinates followed by a report in March 1986, pages 691-692 of the preparation of corresponding phosphine oxides with the same catalyst system.